1. Field of the Invention
This invention is a magnetic data storage fixed hard disk drive that uses stationary Microhead Array Chips in place of conventional "Flying-Heads", conventional "Rotary Voice-Coil Actuators", or other conventional "Servo-Tracking" mechanisms. Every "Microhead Array Chip" has a minimum of one thousand or a maximum of four billion individual and addressable microhead read and write data-transducers built into it. The hard disk drive unit assemblies using the Microhead Array Chip could have as few as two or as many as twenty-eight Microhead Array Chips installed within each hard disk drive unit assembly. The Microhead Array Chip hard disk drive unit assemblies will have at least one storage disk-platter with two disk-platter data-surfaces containing a multiplicity of concentric data-tracks, which are rotated at a substantially constant angular velocity.
In addition, Microhead Array Chips are installed using specially designed circuit boards. These specially designed circuit boards are used to position a Microhead Array Chip into a stationary fixed location over each one of two disk-platter's data-surfaces. The multitude of Induction Channel Coils and Magnetoresistor microheads located inside the Microhead Array Chips are design to be linearly positioned with a location across the top center length of an entire Microhead Array Chip. While disk-platter, radial-width determines the total-length of the Microhead Array Chips that are installed into Microhead Array Chip hard disk drive unit-assemblies. Therefore, the length of the Microhead Array Chips will vary with different disk drive data-platter sizes and hard disk drive designs.
Furthermore, the total number of microheads within a Microhead Array Chip's "Microhead Array" will determine the total number of available tracks on and across it's hard disk data-platter's data-surface (i.e. 65,000 microheads would equal 65,000 cylinder/tracks). Moreover, a Microhead Array of sixty-five thousand micron sized microheads would measure about "2.358" inches in length, giving a hard disk drive using the Microhead Array Chip's design a 3.5-inch hard disk drive form-factor. All Microhead Array Chips installed into a hard disk drive unit assembly are stationary and positioned approximately one-micron above and oriented perpendicular to the hard disk drive's data-platter data-surfaces. The microheads contained within a Microhead Array would also have a fixed microhead-to-microhead distance of one-micron. Moreover, a distance that is measured from a microhead's Magnetic-Flux Concentration Tip centerline to the microhead's Magnetic-Flux Concentration Tip centerline that is linearly next in line. Every microhead located within a Microhead Array will also have a head-gap distance of "0.5" microns. Furthermore, these measurements are a-typical for every Microhead Array Chip that is installed in a hard disk drive unit assembly. In addition, standard (CMOS) or "Complimentary Metal-Oxide Semiconductor" lithography, etching, and masking techniques are used to manufacture the Microhead Array Chips containing the previously mentioned microhead arrays.
Furthermore, as demonstrated in prior art, conventional Flying-Head assemblies (i.e., sometimes called a Head Stack Assembly) are simultaneously moved to or from various data-track locations during the execution of a host-requested read or write-data disk operation. Conventional technologies will use a Rotary Voice-Coil Actuator or what is sometimes called a "Rotary Positioner" to accomplish these track to track movements. However, during a Microhead Array Chip's host-requested read or write-data disk operation, the mechanical movement of a Microhead Array Chip's microheads to or from a hard disk drive's various data cylinder/track locations is unnecessary. Moreover, because the Microhead Array Chips having a multitude of stationary microheads would already have ready for use one of its stationary microheads already in position at that host-requested data track/cylinder location. Unlike the conventional electromechanical head switching and head-positioning of a Rotary Voice-Coil, the Microhead Array Chips will switch from one-microhead to another electronically.
In addition, a Microhead Array Chip hard disk drive's cylinder/track address-numbers and the Microhead Array Chip hard disk drive's microhead address-numbers are in reality the same address numbers, at least for the purposes of the Microhead Array Chip design they are. For example, when a Microhead Array Chip hard disk drive's "Disk Controller" addresses a single stationary microhead within a selected Microhead Array Chip's Microhead Array, during a host-requested disk operation, the previously mentioned Disk Controller is not only selecting a microhead with a specific address, but is also selecting the cylinder/track that is located directly underneath its fixed position, which also happens to have the same address number.
Moreover, during a host-requested read or write-data disk operation the Disk Controller will receive from the host-system data-address information. This data-locating data-address information communicates to the Disk Controller which stationary Microhead Array Chip is positioned above the particular cylinder/track data-sector area containing host-requested data or host-requested data-space that is empty. The "Printed Circuit Board" (PCB) containing the Disk Controller used by the Microhead Array Chip design forwards this address information to its "Address Controller" for translation. When a selected Microhead Array Chip receives a translated microhead address from the PCB's Address Controller, the selected Microhead Array Chip responds by latching and decoding that address. The decoding of a microhead's address will cause the selection of a single microhead. Consequently, the selected microhead will have the same physical-location and address-number as the host-requested cylinder/track containing data-sectors of requested data or available for recording data-areas. Furthermore, once the microhead positioned over the host-requested data-area is selected the read or write disk operation is executed.
In addition, every Microhead Array Chip installed into a Microhead Array Chip Hard Disk Drive's unit assembly is a fully integrated and self-contained CMOS device. The Microhead Array Chips are designed to be fully-integrated semiconductor devices with the microhead arrays, the addressing latching, the address decoding, the address buffering, the microhead selecting, the microhead switching, the signal amplifying, and the data I/O control circuitry all built into a single CMOS chip-package. Its because the Microhead Array Chips are fully-integrated that the Microhead Array Chips can execute "150" nanosecond "track-to-tack" switching operations (i.e., what is sometimes called in conventional hard disk drive design terminology average-seek-times). In addition, the Microhead Array Chip hard disk drive design will use an "ID-less" sector-tracking system for the sector tracking of sector-locations. Moreover, an ID-less sector-tracking system has several advantages over the conventional "ID After Wedge" or "ID Before Sector" methods of typical sector tracking. For example, the lack of an (ID) "Identifier" field, which is normally written to the data-surfaces of a hard disk drive's data-platters, will regain approximately 4% of the hard disk drive's data-surface real estate for end-user data-storage. Furthermore, because no "Sector-ID" has to be read or corrected during a disk operation, in case of an error, the overall throughput of a Microhead Array Chip based hard disk drive is also increased.
2. Description of Prior Art
Hard disk drives, particularly fixed hard disk drives, are valued because of several factors. Including, the hard disk drive's size (i.e., sometimes referred to as "form factor"), data storage capacity, random access times (i.e., sometimes referred to as "access time" or "average-accesstime"), cost per byte stored, and "Mean Time Before Failure" (MTBF) as it is sometimes called. When data-tracks are arranged as concentric-circles on a circular storage data-surface, its outer-tracks or track circles are longer and, therefore having greater numbers of magnetic-storage cell domains available than on the inner-tracks. And when data-storage disk-platters are rotated at a constant angular velocity the data transducers' head-sliders will fly at a faster and somewhat higher altitude above the disk-platters' outer-tracks, where relative head to disk velocity is greatest. However, when data-storage disks are rotated at a constant angular velocity the data transducers' head-sliders will fly at a slower and somewhat lower altitude above the disk-platters' inner-tracks, where relative head to disk velocity is at a minimum.
Moreover, one known way to increase a hard disk drive's data storage capacity is to divide the data storage surfaces into radial data-zones of concentric tracks, which optimizes the data transfer rate to the smallest track (i.e., innermost track) within each particular radial data-zone (i.e., sometimes called "zoned data recording"). Typically, the number of data-sectors or data-fields within each track may vary from zone-to-zone. Therefore, in order to switch from data-zone to data-zone, it is necessary for the hard disk drive to adapt itself in real-time to a different number of data-sectors and too new data transfer-rates. Other known ways to increase data storage capacity, includes varying disk-rotation in function of the radial position of an optical data-head while maintaining a data transfer-rate as substantially constant, as in "Optical Disk" technologies. As opposed to varying the data transfer-rate with each data-track in function of the radial position of the data transducer heads while maintaining a disk-rotation as substantially constant, as in "Fixed Disk Flying-Head" technologies.
In addition, other issues confronting the designer of a hard disk drive might include head positioning and data-block transfer. Moreover, a flying data head's positioning is typically carried out with a "Head Positioner" or Rotary Voice-Coil Actuator and normally involves "track seeking operations" for moving its Head-Stack from a departure track to a destination track. Moreover, this is done throughout the radial-extent of the storage area of a hard disk drive's data-platters, while using data-track following operations for causing the previously mentioned Head-Stack to follow precisely one particular data-track during data-block reading or writing disk operations. To provide precise Head-Stack positioning, during both data-track seeking and following, some servo information must be provided to the Rotary Voice-Coil Actuators mechanism. This information may be contained on a special data-surface written exclusively with servo-information (i.e., sometimes called a "dedicated servo surface").
In addition, servo information may be externally supplied by an "Optical Encoder" coupled to the "Head-Stack positioning Arm". In addition, servo information may be supplied from servo information interspersed or embedded among the data fields within each data-track. One other approach is provided by the "Open Loop Stepper-Motor" Head-Stack positioning servo. In this approach, the positional stability of the transducer data-head at each selected data-track location is provided by the electromagnetic detents of a hard disk drive's Stepper-Motor. When servo-information is embedded on a data-surface having zoned-data recording, complications may arise in the reliably of providing robust servo head position information. Therefore, there must be sufficient embedded information to provide stability to the "Servo Loop" and to provide position responses during high-speed portions of track-seeking and track-following operations so that velocity or position profiles may be adjusted, based on present head-velocity, or position at the time of the sample.
Typically, if the servo-information is recorded at the same data-rate and within a positional relationship with the data-blocks, as has been conventionally employed, the servo-architecture is normally complex enough, in the sense of having information, to successfully switch data-rates and servo positions. However, if regularly spaced servo-information were radially placed across data-storage surfaces, while splitting some of the data-fields on those surfaces into segments, when data-zones are crossed-over complications could arise when trying to read each "Split Data-Field" as a single data-block. Furthermore, in order to read Split data-fields data-platter rotational-velocity must be carefully monitored and maintained at a predetermined constant angular velocity.
In addition, the previously mentioned data-fields are conventionally managed by a "Data Sequencer". A typical Data Sequencer may include an "Encoder and Decoder" for transforming (NRZ) "Non-Return to Zero" data into a coded data-formats. For example, such as a three-to-two 1,7 (RLL) "Run Length-Limited" code to achieve a compression of data relative to the "Flux-Transition Density" on a data-surface (i.e., 1,7 RLL coding is based on three code-bits or groups for two non-encoded data-bits, but results in a four-to-three overall data compression rate and therefore permits more data to be recorded on a disk-platter's data-surface per the number of "fluxtransitions" that may be contained within data-surface "Magnetic-Storage Domain-Cells"). A Disk Controller's Sequencer conventionally performs the task of decoding "Data-Sector" overhead information in order to locate a desired storage location, and to obtain information relating to the correctness or validity of data read back from that storage location. Typically, implemented as a state machine, a Sequencer conventionally monitors all incoming data-flow to locate a data-ID's "Preamble-Field", a data-ID's "Address Mark", a data-ID's "Sector-Field", a data-ID's "Data Field", and usually a small number of "Error-Correction-Syndrome" bytes appended to the end of the previously mentioned Data-Field.
In addition, the Disk Controller's Sequencer will cause the appropriate action to be taken when each of the fields is located. For example, if a data-block from a Data-Field of a particular track and sector is being sought, the Sequencer compares incoming Sector-Field information with sought after sector information stored in a register. Moreover, when a positive comparison occurs the Disk Controller's Sequencer will cause the bytes read from the Data-Field via a data-transducer head and Read Channel to be sent to a "block buffer memory" location, and the Error-Correction-Code Syndrome remainder-bytes to be checked. If there are no detected errors in the data-bytes as determined by analyzing the (ECC) "Error Correction Code" remainder-bytes, then the data-block is sent from the buffer memory to the host-system computer through a suitable interface, such as the (SCSI) "Small Computer System Interface" or (IDE/ATA-2) "Integrated Drive Electronics/AT Attachment" interface.
Moreover, in conventional hard disk drives, each sector is handled individually in response to specific-input from a supervisory microcontroller. Typically, as a particular sector is being read, the microcontroller would inform the Disk Controller's Sequencer whether to read or not read the next adjacent data-sector, in other words, microcontroller intervention would occur for every data-sector. Moreover, this is done with a programmable "Sector-Counter", which is preset by the previously mentioned microcontroller to a desired sector-count, then the Sequencer would process sectors sequentially until the count in the Sector-Counter was reached. Some hard disk drives do not use or normally include the complication of zoned-data recording and Split Data-Fields. Positioner stability in some hard disk drive designs is provided by an "Optical Encoder" coupled between a rotary head positioner and the drive-base, which foregoes the use of "Embedded Servo-Sectors", as is conventional in some art.
However, while "split-data recording" schemes have been proposed in prior art, recent proposals have appointed the microcontroller with the responsibility of managing each Split Data-Field layout in real-time. This leads to tremendous levels of bus-traffic between the microcontroller and the Disk Controller's Sequencer during reading and writing disk operations. This precludes the microcontroller from performing other very useful tasks, such as "head-positioning servosupervision", error-correction, and command-status exchanges with the host-system computer over a hard disk drive's "interface-bus-structure", to cite a few examples. However, this prior art approach would require a separate data-transference microprocessor, meaning that at least two microprocessors would be required to implement overall hard disk drive architecture.